topic Re: cannot disable watchdog in PT60 in 8-bit Microcontrollers

cannot disable watchdog in PT60

IlConte — Mon, 03 Feb 2014 08:33:52 GMT

Dear all,

I have a S08PT60 and at the start of code, I disable the watchdog timer, but, after 6,2 ms the cpu reset.

I think that there is a error in my startup code . . . . but i don't find it !!

This is the my simple code:

; Include derivative-specific definitions

INCLUDE 'derivative.inc'

; export symbols

XDEF _Startup, main

; we export both '_Startup' and 'main' as symbols. Either can

; be referenced in the linker .prm file or from C/C++ later on

XREF __SEG_END_SSTACK ; symbol defined by the linker for the end of the stack

; variable/data section

MY_ZEROPAGE: SECTION SHORT ; Insert here your data definition

; code section

MyCode: SECTION

main:

_Startup:

LDHX #__SEG_END_SSTACK ; initialize the stack pointer

TXS

ldhx #$C520

sthx WDOG_CNT ; First part of the WDG unlock sequence

ldhx #$D928

sthx WDOG_CNT ; Second part of the WDG unlock sequence

lda #$04

sta WDOG_TOVAL ; 4 ms di time out

lda #$01

sta WDOG_CS2

lda #$00

sta WDOG_CS1 ; Disable watchdog

lda #%00100000

sta PORT_PTCOE

lda PORT_PTCD

eor #$20

sta PORT_PTCD ; reset check

eor #$20

sta PORT_PTCD ; reset check

eor #$20

sta PORT_PTCD ; reset check

CLI ; enable interrupts

mainLoop:

; Insert your code here

NOP

BRA mainLoop

I have uset the PC5 for verify if the cpu reset, and it is reset every 6,2 ms

Please help me !!

Thanks

Stefano

Re: cannot disable watchdog in PT60

iansmusical — Mon, 03 Feb 2014 10:19:44 GMT

Ciao Stefano,

I haven't checked but it's possible that you are not using the correct watchdog timer unlock code(s), as I understand there can be different versions for each S08.

Ian

Re: cannot disable watchdog in PT60

IlConte — Mon, 03 Feb 2014 12:40:51 GMT

Unfortunately the code is correct !!

Re: cannot disable watchdog in PT60

iansmusical — Mon, 03 Feb 2014 14:10:19 GMT

Hi Stefano,

Having now looked at the PT60 reference manual I'd agree with you that the code is correct and within the stipulated timings. Of course one hopes that the code in the reference manual is correct in itself ;-) The only difference I can see between your code and Freescales is the following line:

WDOG_TOVAL = 1000; // setting timeout value

You're setting 4 hex and they 1000 decimal?

Ian

Re: cannot disable watchdog in PT60

IlConte — Mon, 03 Feb 2014 15:30:19 GMT

Solved !!

The problem it isn't the value, but the dimension of WDOG_TOVAL, for takes effect it is necessary to write all register, and I wrote only the low of WDOG_TOVAL

Thanks for making me understand the differences and bringing me on the right track.

Stefano